That seems to demonstrate PetaMem's point. "Programming" dropped to 25% of its maximum (the "factor of 4" PetaMem mentioned). Which makes "Perl tutorial"'s 20-fold fall a reflection of an approximate 5-fold relative decline in popularity.
But perhaps I misunderstood your point. That wouldn't be a big shock to me since you included zero words of explanation.
Indeed, and on purpose. Is programming more or less popular than it was in 2004? Based on that chart, you might expect that for every four people you knew programming in 2004, three of them have stopped. Maybe that's true, but it doesn't seem right to me.
If Google were the only way people found information, or if the we knew the right search queries to group together for a complete picture of what people searched for, or how many distinct people searched for tutorials, we might have a clearer picture. Alas, the world isn't what it was in 2004.
We don't even know the relative market share of various languages in 2004 versus today, nor absolute numbers, nor even the number of languages a polyglot knows to a competent extent, nor the overlap.
Please note I'm not saying that Perl has or hasn't lost marketshare in absolute or relative terms and I'm not suggesting that advocacy is or isn't needed. What I am saying is that I think we don't have an empirically measured context in which we can determine what needs to be done (if anything) or if our efforts will make a difference.
So your point really was as simplistic as "see, this graph slopes downward too.... mumble... FUD...". That is disappointing.
Yes, we aren't omniscient. These numbers might have nothing to do with reality. Heck, you might even just be a figment of my fevered imagination.
And that's a pretty pathetic argument in response to a prediction that the baseline drop will be to around 25% and so the many-fold greater drop for some "perl" searches is actually evidence (not proof) of a real decline. Especially when the only thing you offered was a graph that confirms the stated prediction.
I'll be happy if somebody steps up and comes up with things that actually result in Perl regaining more popularity (preferably by Perl actually offering extremely practical solutions for most of the things identified over a decade ago as things that it would be great for Perl 6 to "solve"). I strongly doubt such would come from me, even if I tried (I suck at "sales"). And I'm mostly not interested in arguing about it (beyond pointing out when I see basic arithmetic being denied).